Facebook can't tell elbows from breasts. It took one photo to expose the fact.

A Facebook community page called "Theories of the deep understanding of things" tested the social network's ability to discern which images are considered "indecent material" under its terms of service. The result showed Facebook can definitely make mistakes in classifying certain images as indecent.

The page posted a visually tricky photo of a woman who appears to be flashing her soapy breasts in a tub. If you look closer, however, your eyes will tell your brain that you're looking at pinkish elbows , not areolas. Apparently, Facebook moderators did not take a second look. Either that, or they had to look a third and a fourth time.